In many sports, for example, winter sports such as snowboarding and skiing, users bind their boots to a sporting apparatus such as a pair of skis or a snowboard. Conventional snowboard bindings are generally classified as either high back bindings or plate or step-in bindings. In such bindings, it is generally desirable to have a comfortable and secure attachment to the apparatus that is easily engaged and disengaged. Although the present invention will clearly have applications in fields other than snowboarding, including, in particular, other sports equipment applications, the present ratchet design was originally developed for snowboard binding applications; and for purposes of disclosing and teaching the operation of the invention, the ratchet will therefore be described with reference to snowboard bindings.
In snowboarding especially, a tight and secure binding of the boots to the snowboard is important. If there is too much slack or play in the binding attaching the snowboarder to the snowboard, then the snowboarder will not be able to control the snowboard as precisely as is desired. A snowboarder's boot is held to the snowboard in a binding. Most snowboard bindings utilize a cradle that is bolted to the top of the board that receives the snowboarder's boot. Typically, two straps extend around the top of the boot—one at the instep and the second at the toe—to secure the boot to the snowboard. Unlike ski bindings, the snowboard boot binding generally will not release the boot from the binding during a fall. In fact, it is generally desirable that the binding straps hold the boot securely enough that the boot cannot inadvertently slip out of the binding, even if the snowboarder falls during a run.
Many types of snowboard bindings have been developed to secure the snowboarder's boots to the snowboard. Because of the importance of a tight coupling between the snowboard boots and the snowboard, buckles for snowboard bindings frequently include tightening devices that provide some mechanical advantage to facilitate strap tightening. For example, various strap designs have been developed that utilize a ratchet-type buckle that mounts to a first binding element, such as an instep pad, and a second binding element or strap having a plurality of transverse ridges, or teeth, often referred to as a ladder strap.
In prior art ratchet buckles, a lever having a plurality of teeth on one end is pivotally mounted to a buckle body that slidably receives the ladder strap. Such ratchet buckles are disclosed, for example, by Dodge in U.S. Pat. Nos. 5,416,952 and 5,745,959, and by Allsop in U.S. Pat. No. 3,662,435. The ladder strap is inserted into the buckle body and the lever is pivoted to engage the strap teeth and advance the strap. A separate holding device (i.e., a pawl) is provided to engage the strap teeth and prevent backward movement of the strap as the lever is lifted away from the strap and returned to the start position, to re-engage the strap, and be re-pivoted to further tighten the strap, as necessary. A disadvantage of such prior art ratchet buckles is that they engage and disengage the strap teeth multiple times during the tightening process, which generates wear and tear on the ladder strap, which is typically made from a softer material. Multiple engagements and disengagements of the strap also increase the likelihood that the device will slip during tightening, either due to misalignment of the mechanisms with the strap, wear and tear on the strap or buckle, or due to foreign matter such as dirt and ice interfering with a proper engagement. Another disadvantage to such devices is that the toothed driving end of the lever is typically disposed a distance from the holding device, so that the strap must be inserted a fair distance into the strap to engage both the lever and the holding device before the lever will operate to tighten the strap.
Other ratchet-type buckles have been developed that utilize a plurality of spring-loaded pawls that alternately drive (tighten) and hold the ladder strap. Such a buckle is disclosed, for example, by Lin in U.S. Pat. No. 5,779,259. The buckle taught by Lin, however, has the same disadvantages identified above. Multiple engagements and disengagements of the ladder strap will increase wear on the strap, and both of the longitudinally spaced-apart pawls must be engaged by the strap for the device to operate properly.
Another ratchet buckle mechanism is disclosed by Olivieri in U.S. Pat. No. 4,547,980, which teaches a device having a rotatable sprocket that engages transverse teeth on a ladder strap. In Olivieri, the sprocket is rotatably mounted to the buckle, which is prevented from rotating in one direction by a spring-loaded holding pawl. A driving pawl is provided on a pivotable lever, which is pivoted to rotatably drive the sprocket and tighten the strap. However, the device disclosed by Olivieri has no apparent means to release the strap. Although the inventor states that to release the strap it suffices to depress the back end of the driving pawl, the disclosed action would not release the locking pawl, and therefore the strap will not be released. It appears that to release the strap the user must press the driving pawl and pull back the holding pawl, which may be very difficult, particularly if the user must simultaneously pull on the ladder strap. Moreover, the sprocket will still engage the strap, and will therefore rotate as the strap is pulled out, which increases wear on the buckle and strap.
There remains a need for a ratchet buckle for use with a ladder-type strap that minimizes wear and tear on the strap and is easily releasable.